Electron discharge device



Nov. 29, 1938.

v R u. CLARK ELECTRON DISCHARGE DEVICE Filed July 6, 1957 I. 1 v v u v f H v 3 lllllllllll 47lflllllllll H 1T v... l v. I

dwww'a Patented Nov. 29, 1938 UNITED STATES PATENT OFFICE 1 Claim.

The present invention relates to electron discharge devices and more particularly to a novel construction of vapor electric tube primarily adapted for the generation or by -passing of appreciable amounts of electric current of either an alternating or pulsating nature, when propcrly excited by direct or alternating current from any suitable external source, as shown in my 'copending application.

One or" the objects of the present invention is to provide a novel construction of vapor electric tube employing a readily ionizable atmosphere, in combination with a common electron emitting means, a plurality of associated grids and :5 anodes and means for permitting a free but controlled flow of electrons from substantially the entire surface of the emitting means.

Another object of the present invention is to provide in a vapor electric tube having multiple 0 grid and anode elements, a common cathode or electron emitting means so constructed and arranged as to'permit a free and complete flow of electrons from substantially its entire emitting surface to one plate at a time.

The above features, advantages and capabilities of my present invention will become apparent from a description of the accompanying drawing in which I have illustrated one form of my invention but the form there shown is to be understood as illustrative only and not as defining the limits of my invention except as expressed or intended to be expressed in the appended claim.

Fig. 1 is a view partly in section of an electron discharge device illustrating an embodiment of my invention.

Fig. 2 is a cross sectional view showing a modification thereoi'.

Referring to the drawing in detail there is disclosed an evacuated bulb I in which is mounted a common cathode or electron emitting means provided with leads 3 and 4 for supplying heater excitation. This common cathode may be heated either indirectly or as a filament. Surroundor encompassing the electron emitting means are provided multiple grids 5 and 6 having heat radiators l and 8 connected to lead wires 9 and if respectively. Surrounding these grids are plates or anodes H and I2 connected to lead wires l3 and M, respectively. The grid heat radiators l and 8 are employed to maintain the grids cool and to reduce the grid emission.

There is provided a non-conducting partition l5 having an outer diameter greater than that of the plates. This partition has a central opening which forms a. close fit or contact with the outer surface of the common cathode.

The grids 5 and 6 as well as plates or anodes H and i2 abut against the partition l5 which acts as a screen or baffle to prevent stray arcs between the adjacent tube sections. It also serves to center and anchor the multiple grids and plates.

The common cathode or electron emitting means may be of the oxide coated type, of caesiated metal, or of any other type suitable for use with alkali metal vapors. In the disclosed embodiment it comprises a tube-like sleeve 55 extending through the partition enclosing a heating coil H, which coil is connected to the sleeve it by suitable connection l8, as shown.

The grids 5 and 6 are connected through a by-passageway which extends from a point within one grid outwardly through the partition l5 and into the adjacent grid, such passageway being of a size and displacement sufficient to by-pass the flow of electrons and ions from one portion of the cathode to another at such times as the grids prevent simultaneous emission to the plates. In the particular form shown in Fig. 1 for accomplishing this object I have shown two such passageways l9 and 2B which are of arcuate shape and extend through the partition I5 outside of the periphery of the grids but have their intake and discharge ends terminating within the periphery of the grids.

It is obvious that these communicating passageways may also extend outside the plates if desired, or by properly shielding the plates and leads a virtually closed passage will exist from either end of one grid, around the tube structure, back to the end of the other grid permitting the flow of cathode emission, provided the grid end shields have suitable openings or ducts therein.

In Fig. 2 a modified form is shown in which the partition 2| extends vertically instead of horizontally, as shown in Fig. 1 and the bypassageways 22 and 23 corresponding to the bypassageways I9 and 2B of Fig. 1 are arranged horizontally instead of vertically as shown in Fig. 1 and pass through the partition at a point outside the periphery of the grids and arranged to have their intake and discharge ends terminating within the periphery of the grid, and as in Fig. 1, these Icy-passageways are of a size and displacement sufficient to bypass the flow of electrons and ions from one portion of the cathode to the other at such times as the grids prevent simultaneous emission to the plates. By this arrangement the free flow of electrons from substantially the entire surface of the cathode or electron emitting means is permitted to one plate at a time when the tube is in operation notwithstanding the partition tightly fits around the cathode and notwithstanding the by-passageways extend outside the periphery of the grids.

In my preferred form the anodes and grids are made of compressed and sintered powders of conducting materials including rhenium or other metals of high oxidizing temperatures, and poisonous to electron emission, and carbon, all proportioned to afford minimum electron emission and at the same time a maximum heat radiation from such parts.

The particular form disclosed may be employed with satisfactory results in oscillating circuits to convert the input into alternating or pulsating current from applied direct current source. This type of tube is particularly important in low voltage oscillating circuits such as are necessarily employed in operating radio sets.

Having thus described the invention, I claim:

A vapor electric tube having an envelope and a readily ionizable atmosphere, comprising a plurality of grids and cooperating plates and a common electron emitting cathode, an insulating partition adapted to be mounted intermediate said grids, and a means forming by-passage-Way outside the periphery of the grids and connecting with sections of the cathode, said passageway being of a size and displacement sufiicient to bypass the fiow of electrons and ions from one portion of the cathode to the other at such times as the grids prevent simultaneous emission to the plates.

RICHARD U. CLARK. 

